STUDIES ON SPORE IMMOBILIZATION CONDITIONS FOR DEVELOPMENT OF PENICILLIUM-CHRYSOGENUM BIOPARTICLES

Cultural conditions in shaking flasks for obtention of Penicillium chr ysogenum IFO 8644 bioparticles of suitable size for its utilization in tower type fermentor were set up. Immobilization was realized by spor e entrapment in selected diatomaceous earth particles ranging from 125 to 292 mum. The effect of agitation speed, phosphate concentration an d spore concentration on the bioparticle diameter was examined in a 72 hours culture at 26-degrees-C utilizing medium with sucrose and corn steep liquor as main components. Experiments were performed according to central composite design technique and the statistical analysis of the results enabled to correlate bead size with the studied variables through an empirical equation describing a second order model. It was observed that the main variable affecting bioparticle diameter is the spore concentration whose increase reduces the pellet size. Furthermor e, experiment in which only the spore concentration was varied confirm ed the general pattern predicted by the empirical expression establish ed through the factorial design experiments.